Process for controlling dye gradation in color photographic element



United States Patent 01 ice 3,520,690 Patented July 14, 1970 ABSTRACT OFTHE DISCLOSURE A process for controlling the gradation of dye images incolor photographic processing employing a developer containingp-phenylencdiamine or a derivative thereof, which comprises processingwith a developer additionally incorporating at least one member selectedfrom the group consisting of compounds represented by the generalformulas COOM wherein X represents a member selected from the groupconsisting of H, OH, and NH and M represents a member selected from thegroup consisting of H, Na, K, NH other mono-valent positive atoms andmono-valent atomic groups.

and

The present invention relates to a process for processing colorvphotographic elements and more particularly to an improved processingmethod in color photography for controlling the gradation of dye imagesand the graininess thereof.

A conventionally employed process for processing the usual silverhalide, color photographic elements, after exposure, for obtaining colorimages includes the step of processing the exposed color photographicelement in an alkaline solution. The solution contains a primaryaromatic amine type color developer in the presence of a coupler andforms a color image by the reaction of the coupler and the thus formedoxidation product of the color developer.

However, on comparison with a black and white photographic imageobtained by applying the usual black and white development process, thedensity of the color photographic image obtained by the abovementionedcolor development is generally extremely high, by the high extinctioncoefiicient of the dye, and the gradation thereof is generally hard.Accordingly the phenomenon of hardening in gradation of the color image,incidental to color development for color photographic elements, must besettled.

The simplest method for overcoming such a difficulty is to reduce thequantity of silver halide in the emulsion layer of the colorphotographic element to control the gradation to a normal state.Therefore, the content to silver halide in a color photographic elementis usually markedly less than that which is practical and general in ablack and white photographic element. However, it is not preferable toreduce the quantity of silver halide, since there are substantialdrawbacks, namely, graininess becomes coarser and resolving powerbecomes lower.

In order to overcome such drawbacks, the grain size of the silver halidemay be fined. However, the fining of the silver halide particle isinevitably accompanied by a reduction in sensitivity, which makes theemployment of such a process dilficult except for a specific purpose.

Therefore, for obtaining a color image in which the graininess andresolving power are generally good and the graduation is not too hard, aprocess is desired wherein the gradation of the color image is softenedwithout reducing the quantity of silver halide.

For satisfying this purpose, a process has already been provided inwhich the processing is conducted while incorporating a compound havinga gradation controlling action, as will be shown below, in the colordeveloper or in the light-sensitive emulsion layer.

As examples of compounds to be incorporated in the color developer,there are described a series of compounds, such as1-arnino-8-naphthol-3,6-disulfonic acid in US. Pat. 2,689,793. However,these compounds have the drawback that the rate of reaction thereof withthe oxidation product of the developer is fast and the control range ofgradation is narrow.

Further, compounds, such as 2,6-dihydroxy isonicotinic acid, describedin US. Pat. 2,741,832, are less troubled by the foregoing drawback andhave excellent gradation controlling ability, but they are not yetavailable in sufiicient quantity.

As examples of compounds to be added to the color developer or thelight-sensitive emulsion layer, there are described {3 naphthols inGerman Pats. 1,123,558 and 1,099,350, but they are also not available insufiicient quantity.

Furthermore, there is reported in German Pat. 1,155,- 675 that compoundshaving a substituted-type active methylene are effective for such apurpose.

A main object of this invention is to provide a novel gradationcontrolling compound having better properties than known gradationcontrolling compounds.

The inventors have found that the compounds shown by the followinggeneral structural formulas have not only very excellent effects in thecontrol of gradation, the improvement of graininess and the increase ofresolving power, but also are capable of enlarging effectively the rangeof gradation control, which contribute to the improvement of thequalities of photographic dye images more effectively than conventionalgradation controlling compounds.

The compounds used in this invention are represented by the followinggeneral formulas:

COOM

H. OH

I fi coon 3 wherein X represents H, OH or NH and M represents H, Na, K,NH 01' other mono-valent positive atom or atomic group.

Typical examples of the compounds shown by the Formula I are as follows:

(1) Salicylic acid (2.) Sodium 4-aminosalicylate COONa (3)4-oxysalicyclic acid COOH Typical examples of the compounds shown by theFormula II are as follows:

(4) l-hydroxy-Z-naphthoic acid (5) Sodium l-hydroxy-6-amino-2-naphthoateGOONa The optimum amount in which the compound should be used as anadditive is influenced by the kind and the concentration of the couplerto be employed, the kind of developing agent, the pH of the processingsolution, and the extent of gradation to be controlled, but, in general,the amount of 0.1-3 g. of the compound per one liter of color developeris applicable.

An amount of the compound less than the above range gives only a pooreffect and an amount more than this range tends to reduce the colordensity too much. For obtaining the usual gradation an amount of 0.8-1.2g./ liter is preferable.

The compound of this invention may be applicable for processing a colorphotographic film or a color photographic printing paper of the typewherein a coupler is incorporated in the emulsion layer of the colorphotographic element, as well as a color photographic film of the typein which a coupler is incorporated in a processing solution.

The invention will be explained more practically by the followingexamples, but it should be understood that the invention is not limitedto them by any means.

EXAMPLE 1 To a film support of cellulose acetate were applied ared-sensitive gelatino silver bromo-iodide emulsion, a green-sensitivegelatino bromo-iodide emulsion, a yellow filter layer composed ofcolloidal silver capable of absorbing blue light, and a blue-sensitivegelatino silver bromoiodide emulsion, successively, in this order toprovide a multi-layer color photographic film, which was exposed bymeans of a sensitometer and subjected to the following processings:

First and second developers: I I N-Methy1-p-aminophen0l /2 sulfate-2.0g.

Sodium sulfite90.0 g. Hydroquinone8.0 g. Sodium carbonate(mono-hydrate)52.5 g. Potassium bromide5 .0 g. Potassium thiocyanatel.0g. Water to make 1 liter.

Cyan color developer:

Sodium sulfite5.0 g. 4-amino-3-methyl-N,N-diethylanilinehydrochloride0.6 g.

Potassium bromide-0.25 g. Sodium carbonate (monohydrate)-15.0 g.Potassium iodide (0.1% aq. soln.)--2 ml.1.5-dihydroxy-2,6-dibromonaphthalene1.2 g. Sodium hydroxide2.0 g. Waterto make 1 liter.

Yellow color developer:

Sodium sulfiteS.0 g. Y

4-amino-N,N-diethylaniline hydrochloride-25 g.

Potassium bromide-4.0 g.

Potassium iodide (0.1% aq. soln.)-5 ml.-

1-benzoy1-4-(p-toluenesulfoamido) acetanilide1.2 g.

Sodium hydroxide-2.0 g.

Water to make 1 liter.

Magenta color developer:

Sodium sulfite5.0 g.

4-amino-3-methyl-N,N-diethylaniline hydrochloride-2.0 g.

Potassium bromide-O.2 g. I I

l-phenyl-3-(m-nitrobenzoylamino)-5- pyrazolone-1.4 g.

Sodium hydroxide2.5 g.

n-Butylamine5 ml.

Water to make 1 liter.

Bleaching solution:

Potassium ferricyanide-AOO g. Potassium bromide-l0 g. Borax-2 g. r Boricoxide-l g. 1 J Water to make 1 liter. 1

Fixing solution:

Sodium thiosulfate g. Sodium sulfite-lO g. Water to make 1 liter.

The above-mentioned standard processin gs were conducted while addingthe compounds of this invention to 1 the magenta color developer asshown in the following,

table in accordance with the process of this invention and the resultsare shown in the same table.

TABLE 1 Relative Magenta sensitivity Addition develop- Increase ofmagenta Compounds added in amount ing time Gradain coupling magentacolor developer (g./l.) (min.) tion latitude layer None 5 1. 76 0. 84Compound (1) 0. 7 7 l. 55 +0. 15 1. 09 Compound (2) 0.8 7 1. 60 +0. 080. 99 Compound (3) 1. 0 7 1. 64 +0. 11 1. 04 Compound (4) 0. 6 7 1. 63+0. 12 1. Citrazic acid 0. 4. 7 1. 65 +0. 0. 99

In the table, the gradation is shown by the average gradient of the linepassing through the points on the characteristic curve corresponding todensity 0.4 and density 2.0 and the increase in latitude is shown by theincrease in relative value of the difference between the exponentialexposure amounts corresponding to density 0.3 and density 2.5 to thevalue of the standard development. Further, the addition amount is theoptimum amount.

As shown in Table 1, the gradation controlling effect by the addition ofthe compounds in this invention is far better than that of the knownadditive citrazic acid.

More conveniently, by the addition of the compounds of this invention,the sensitivity of the magenta coupling layer is increased, theformation of undesirable coupling which results in color contaminationis prevented and excellent color reproduction can be obtained.

EXAMPLE 2 The multi-color photographic film, as in Example 1, wasprocessed after exposure as in Example 1, but in this case thecomposition of the magenta developer was varied as follows:

Formula A Formula B Composition A further added with 1 g./liter ofsodium 4-amino-salicyalate. The results are shown in the followingtable.

TAB LE 2 Relative sensitivity of magenta Formula of magenta ProcessingIncrease in coupling developer time (min) Gradation latitude layerFormula A 5 1. 83 0 0.85 Formula B 7 l. 65 +0.20 1. 00

As shown in the above table, by the addition of sodium4-amino-salicyate, the gradation of the magenta color image can besoftened, the latitude can be enlarged and high sensitivity is obtained.

EXAMPLE 3 A gelatino silver bromo-iodide emulsion containing a cyancoupler was applied to a film of cellulose acetate Color development6min. at 24 C.

Wash-30 sec. First fixation-4 min. Wash-5 min.

Silver-bleach4 min. Rinse5 min.

Second fixation-4 min. Wash5 min.

The bath formula in the above processings were as follows:

Color developer:

Benzyl alcohol-31 ml.

Sodium sulfite-2 g.

3-methyl-4-amino-N,ethyl N,methanesulfonamidoethylaniline sulfate-1.5 g.

Sodium carbonate (mono-hydra-te)60 g.

Potassium bromide-l g.

Sodium hydroxide (10% )1 ml.

Water to make 1 liter.

Formula (A) having added to it 1 g./liter of sodium 4-oxysalicylate.

Formula (A) having added to it 0.8 g./liter of sodium 4-aminosalicylate.

Formula (A) having added to it 1 g./liter of l-hydroxy-2-naphthoic acid.

Formula (A) having added to it 0.8 g./ liter of sodiuml-hydroxy-6-amino-2-naphthoate.

After processing, the cyan color density of the thus processed film wasmeasured by means of a semidiifuse type densitometer, the results ofwhich are shown in Table 3, wherein the gamma value is shown by thecurve.

8 Formula (C) Formula A having added to it 1 g./liter ofl-hydroxynaphthoic acid.

TABLE 3 F l I P 1 mm Rflatlvefsensl- Bleaching solutioni t t n 0 0 1 1tielei gi recess 5111111.? coi ipl i n g 1i? Gamma'value Potassium fenWanda-100 Sodium acetate-40 g. 8 g: ,2 51 gg Glacial acetic acid--2Q ml.2. 06 0. 85 Potassium bromide-30 g. B 3:82 333.- Water to make 1 liter.

3 Fixing solution: I As shown from Table 3, by the addition ofjjthecom-'f Sodium thiosulfate. :150 g. pounds used in this invention, thegamma value can-be Sodium acetate-70g. considerably reduced, and thelatitude can be enlarged Sodium sulfite10 g. as well. m .Potassiumalurn-2 0 g.

EXAMPLE 4 Water to make; .liter. a v I r I To a film of celluloseacetate were appliedared se I I: a result 'of ineasurement afterprocessing it was tive silver bromo-iodide emulsion containing-.21 cyancouobserved that the gradation was improved, the latitude pler, agreen-sensitive silver bromo-iodide emulsion .co nenlarged and thecolorcontamination was reduced taining a magenta-coupler, a yellowfilter layercontaining as. shown in the ,tollowing table.

Gradation Increase in Relative sens. Processln Formula time (min. (1)(2) (3) A 0 1.75 1.80 1.85 'i ..0 0 0 1.20 v.112 1.15 B 7 1.70 1. s5 1.75 +0.08 +0.15 +0.11 1.35 1. 2.1 1.21 c 8 1.68 1. 60'.= 1. 70' +0.161.30 I 1. 30 1. 21

(1) Cyan; (2) Magenta and (3) yellow. 7

First developer: same as the first developer in,Example 1 Stoppingsolution: I Sodium acetateg, Acetic acid-3 ml. Water to make 1 liter.

Hardening solution:

Potassium alum-30 g. Water to make 1 liter. Color developer: Formula (A)Benzyl alcohol-5 ml. I

Sodium sulfite5 g. Sodium hydroxide (10% )-5 ml. Sodium phosphate-30 g.3-methyl-4-amino-N,ethyl-N,methane-sulfoamidoethylaniline sulfate10 g.Potassium bromide1 g.= V .Ethylene diamine--5 'ml. Water to makel liter.

' 4 Formula (B) added to it 1".5 .g Q/liter '01; sodium Formula vAhaving salicylate.

" What is claimed is:

1. In a process for processing'color photographic elements employing acolor developer containing a member selected from the group consistingof p-phenylenediamine and a derivative thereof, the improvement whichcomprises controlling the gradation of dye images obtained therein byprocessing with a developer additionally incorporating at least onemember selected from the group consisting of compounds having theformula wherein X is a member selected from the group consisting of H,OH and NH and M is a member selected from the group consisting of H, Na,K, NH other monovalent positive atoms and mono-valent atomic groups.

2. The process as claimed in claim 1 wherein the proportion of saidcompound is from about 0.1 to 3 g. per 1"literfof the color developer. I

3. The process as claimed in claim 1"wherei'n the proportion of saidcompound is from about 0.8 to' 1.28"g. per 1 liter of the colordeveloper.

4. The process as claimed in claim 1 wherein-said color developerfurther contains a soluble color coupler. "5. The process as claimed inclaim 1 wherein said com- COOM pound is lhydroxy 2-naphthoieacid. v6.-The= process as claimed in claim 1 wherein said compoundis sodiumI-hydroxy-6-amino 2-naphthoate.

References Cited y UN TE A E P E 2,156,626, 5/1939 Ham1 96566.42,444,803. 7/1948 Bean 96-663 2,728,660 12/1955 Salminenet a1. .96

J. TRAVIS BROWN, Primary Examiner

